U.S. patent number 8,692,032 [Application Number 13/539,041] was granted by the patent office on 2014-04-08 for methods of using tungsten carbide catalysts in preparation of ethylene glycol.
This patent grant is currently assigned to Dalian Institute of Chemical Physics, Chinese Academy of Sciences. The grantee listed for this patent is Jingguang Chen, Na Ji, Yuying Shu, Aiqin Wang, Xiaodong Wang, Tao Zhang, Mingyuan Zheng. Invention is credited to Jingguang Chen, Na Ji, Yuying Shu, Aiqin Wang, Xiaodong Wang, Tao Zhang, Mingyuan Zheng.
United States Patent |
8,692,032 |
Zhang , et al. |
April 8, 2014 |
Methods of using tungsten carbide catalysts in preparation of
ethylene glycol
Abstract
Tungsten carbide catalysts are used in preparation of ethylene
glycol by hydrogenating degradation of cellulose. The catalyst
includes tungsten carbide as main catalytic active component, added
with small amount of one or more transition metals such as nickel,
cobalt, iron, ruthenium, rhodium, palladium, osmium, iridium,
platinum, and copper as the second metal, supported on one or more
porous complex supports such as active carbon, alumina, silica,
titanium dioxide, silicon carbide, zirconium oxide, for conversion
of cellulose to ethylene glycol. The catalyst realizes high
efficiency, high selectivity, and high yield in the conversion of
cellulose to ethylene glycol at the temperature of 120-300.degree.
C., hydrogen pressure of 1-10 MPa, and hydrothermal conditions.
Compared to the existing industrial synthetic method of ethylene
glycol using ethylene as feedstock, the invention has the
advantages of using renewable raw material resources, environment
friendly process, and excellent atom economy.
Inventors: |
Zhang; Tao (Dalian,
CN), Ji; Na (Dalian, CN), Zheng;
Mingyuan (Dalian, CN), Wang; Aiqin (Dalian,
CN), Shu; Yuying (Dalian, CN), Wang;
Xiaodong (Dalian, CN), Chen; Jingguang (Dalian,
CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Zhang; Tao
Ji; Na
Zheng; Mingyuan
Wang; Aiqin
Shu; Yuying
Wang; Xiaodong
Chen; Jingguang |
Dalian
Dalian
Dalian
Dalian
Dalian
Dalian
Dalian |
N/A
N/A
N/A
N/A
N/A
N/A
N/A |
CN
CN
CN
CN
CN
CN
CN |
|
|
Assignee: |
Dalian Institute of Chemical
Physics, Chinese Academy of Sciences (Dalian, Liaoning,
CN)
|
Family
ID: |
41668648 |
Appl.
No.: |
13/539,041 |
Filed: |
June 29, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120283487 A1 |
Nov 8, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12734763 |
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8338326 |
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PCT/CN2008/072892 |
Oct 31, 2008 |
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Foreign Application Priority Data
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Aug 14, 2008 [CN] |
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2008 1 0012830 |
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Current U.S.
Class: |
568/861 |
Current CPC
Class: |
C07C
29/00 (20130101); B01J 23/888 (20130101); B01J
27/22 (20130101); C07C 29/132 (20130101); B01J
23/6527 (20130101); B01J 37/0201 (20130101); B01J
37/08 (20130101); B01J 21/18 (20130101); C07C
29/00 (20130101); C07C 31/202 (20130101); C07C
29/132 (20130101); C07C 31/202 (20130101); Y02P
20/52 (20151101) |
Current International
Class: |
C07C
27/00 (20060101); C07C 29/00 (20060101) |
Field of
Search: |
;568/861 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Direct Catalytic Conversion of Cellulose into Ethylene Glycol
Using Nickel-Promoted Tungsten Carbide Catalysts," Na Ji et al.
Angew. Chem. Int. Ed. 2008, 47, pp. 8510-8513. cited by
examiner.
|
Primary Examiner: Hailey; Patricia L
Attorney, Agent or Firm: Novick, Kim & Lee, PLLC Xue;
Allen
Parent Case Text
This is a divisional application of application Ser. No.
12/734,763, filed May 18, 2010, which is a National Stage of
International Application of PCT/CN2008/072892, filed Oct. 31,
2008, both of which are incorporated herein by reference.
Claims
What is claimed is:
1. A method of catalytic degradation of cellulose, comprising:
obtaining a mixture comprising cellulose, water, and a catalyst;
placing the mixture in a reactor filled with hydrogen; and keeping
the mixture at an elevated temperature for a certain reaction time,
wherein the catalyst has a formula A-WxC/B, in which component A
represents one or more metallic elements chosen from nickel,
cobalt, iron, ruthenium, rhodium, palladium, osmium, iridium,
platinum, and copper, W represent tungsten, and WxC represents
tungsten carbide, wherein 1.ltoreq.x.ltoreq.2, and component B is a
porous support chosen from active carbon, alumina, silica, titanium
oxide, silicon carbide, zirconium oxide, and mixtures thereof.
2. The method of claim 1, wherein a total loading of A-WxC in said
catalyst is 2-85 wt %, a loading of component A in said catalyst is
0.05-30 wt % and a loading of tungsten in said catalyst is 1-80 wt
%.
3. The method of claim 2, wherein the loading of tungsten is 10-60
wt % and the loading of component A is 0.1-5 wt %.
4. The method of claim 1, wherein a mass ratio of the cellulose to
water is in the range of 1:200 to 1:5.
5. The method of claim 1, wherein a mass ratio of the cellulose to
the catalyst is in the range of 1:1 to 30:1.
6. The method of claim 5, wherein a mass ratio of the cellulose to
the catalyst is in the range of 10:1 to 20:1.
7. The method of claim 1, wherein the hydrogen pressure in the
reactor is in the range of 1 to 10 MPa at room temperature.
8. The method of claim 7, wherein the hydrogen pressure in the
reactor is in the range of 3 to 7 MPa at room temperature.
9. The method of claim 1, wherein said elevated temperature is in
the range of 120 to 300.degree. C.
10. The method of claim 9, wherein said elevated temperature is in
the range of 220 to 250.degree. C.
11. The method of claim 1, wherein said reaction time is in the
range of 10 min to 24 hours.
12. The method of claim 11, wherein said reaction time is in the
range of 30 min to 6 hours.
13. The method of claim 1, wherein the cellulose is derived from
biomass.
14. The method of claim 11, wherein cellulose is degraded to form
ethylene glycol.
15. The method of claim 14, wherein the product further comprises
hexahydric alcohol.
16. The method of claim 14, wherein the yield of ethylene glycol is
larger than about 60%.
17. The method of claim 1, wherein component A represents
nickel.
18. The method of claim 17, wherein the loading of nickel ranges
from 1-10 wt %.
19. The method of claim 1, wherein component A represents
ruthenium.
20. The method of claim 1, wherein component A represents iridium.
Description
BACKGROUND OF THE PRESENT INVENTION
1. Field of Invention
The present invention relates to a method of synthesizing ethylene
glycol, and more particularly to tungsten carbide catalysts and the
preparation, as well as the application in the reaction of
preparing ethylene glycol by hydrogenating degradation of
cellulose.
2. Description of Related Arts
Ethylene glycol is an important liquid energy fuel and very
important feed for polyester synthesis. For example, Ethylene
glycol is used for synthesis of polyethylene terephthalate (PET)
and polyethylene naphthalate (PEN). It is also used as antifreeze,
lubricants, plasticizers, surface active agent, etc. Thus it is an
organic chemical material with wide applications. In recent years,
its demand maintains a growth rate of 6.about.7% world widely.
China has a huge consumption of ethylene glycol. In 2005, the
market demand is 5 million tons, accounting for 25% of the world's
total production, nearly 80% of which had to be imported. Ethylene
glycol is one of China's "Ten key imported products".
Currently, industrial production of ethylene glycol is mainly
depending on petroleum as the raw material. The ethylene glycol is
produced via ethylene oxidation to form the epoxyethane, followed
with hydration to form the final product. [Reference 1: Shen,
Ju-hua, Overview of ethylene glycol production, Chemical Technology
Market, 2003, 26, (6), 12-15. Reference 2: Process for preparing
ethanediol by catalyzing epoxyethane hydration, Patent No.
CN1463960-A; CN1204103-C]. This method consumes non-renewable
petroleum resources. Also the producing process includes steps of
selective oxidation and epoxidation, which confronts many technique
difficulties, such as low efficiency, large amount of by-products,
high material consumption and pollution.
Using biomass to prepare ethylene glycol can reduce human's
dependence on the fossil energy resources, because it is
environment friendly and contributing to the sustainable
development of the world. Currently the research of biomass
conversion to ethylene glycol mostly focuses on the raw materials
such as starch, glucose, sucrose, and sugar alcohols. [Reference 3:
Process for the preparation of lower polyhydric alcohols, U.S. Pat.
No. 5,107,018. Reference 4: Preparation of lower polyhydric
alcohols, U.S. Pat. No. 5,210,335.]. These raw materials themselves
are food for mankind, so that using them to prepare chemicals will
cause the conflict between survival and development of the mankind.
In contrast, cellulose is the largest renewable biomass with rich
resources but indigestible for human being, such as agricultural
production, remaining straw and forestry wastes, so that it is
abundant and cheap. The use of cellulose to prepare ethylene glycol
enables a new synthetic method to obtain high value products with
low cost, meanwhile this will not affect the food supply. In
addition, cellulose is formed by polycondensation of glucose units
via glycosidic bonds, containing a large number of hydroxyl. In the
process of cellulose conversion to ethylene glycol, the hydroxyl is
fully retained, so that this transformation process has very high
atom economy. Thus, the conversion of cellulose to ethylene glycol
has a number of significant advantages unmatched by many other
production methods.
However, because the structure of cellulose is much more stable
than other biomass, it is a considerable challenge to convert
cellulose into small molecule polyols with high efficiently and
high selectivity. According to the survey of current literature,
there is no report of any works for the cellulose conversion into
ethylene glycol with high efficiency and high selectivity with
tungsten carbide catalysts.
SUMMARY OF THE PRESENT INVENTION
The main object of the present invention is to provide a kind of
tungsten carbide catalysts and their preparation and application in
production of ethylene glycol from cellulose by hydrogenating
degradation. Cellulose is catalytically converted into ethylene
glycol under hydrothermal hydrogenating conditions, with high
efficiency and high selectivity.
In order to accomplish the above object, the present invention
provides a kind of catalysts for the catalytic conversion of
cellulose to ethylene glycol, which is expressed as: A-W.sub.xC/B.
Wherein the catalytic active component is A-W.sub.xC. A is one or
more metallic elements selected from the group consisting of
nickel, cobalt, iron, ruthenium, rhodium, palladium, osmium,
iridium, platinum, and copper. W.sub.xC is tungsten carbides,
wherein 1.ltoreq.x.ltoreq.2. In the catalyst, the total loading of
catalytic-active metal is 2-85 wt %. The loading of A is 0.05-30 wt
%, and the loading of W is 1-80 wt %. B is a porous support, which
comprises one or more complexes selected from the group consisting
of active carbon, alumina, silica, titanium oxide, silicon carbide,
zirconium oxide.
The catalyst is loaded on the support by impregnating salt
solutions of catalytic active components. The loading of tungsten
is preferably 10-60 wt %, and the loading of the second metal A is
preferably 0.1-5 wt %.
The catalyst precursor obtained by impregnation is dried at
100-160.degree. C., and then heated in hydrogen or methane/hydrogen
(methane concentration in mixed gas is 10-100% v/v) at
600-900.degree. C. for temperature-programmed carburization. The
preferred temperature is between 700-800.degree. C., and the
atmosphere is hydrogen or methane/hydrogen (methane concentration
in mixed gas is 20% v/v), carburization time is no less than 1
hour.
The reaction conditions for the catalytic conversion of cellulose
into ethylene glycol are described as follows: the hydrogenating
degradation of cellulose is performed in a sealed reactor, the mass
ratio of cellulose to water is 1:200-1:5, the mass ratio of
cellulose to catalyst is 1:1-30:1, the initial pressure of hydrogen
filled in the reactor at room temperature is 1-10 MPa, reaction
temperature is 120-300.degree. C., and the reaction time is 10
min-24 h.
The present invention has the following advantages:
1. Cellulose has the most abundant production in nature,
originating from wide sources such as wood, cotton, corn stover,
and crop straw. Using it to prepare ethylene glycol is of low cost.
Moreover, compared to the existing industrial process for the
synthesis of ethylene glycol which consumes ethylene as feed, the
present invention does not rely on fossil energy resources, and has
the advantages of using renewable raw material and being consistent
with sustainable development.
2. The catalyst cost is low, because that tungsten carbide is used
as the main catalytic active component, and a small amount of one
or several transition metals such as nickel, cobalt, iron,
ruthenium, rhodium, palladium, osmium, iridium, and platinum are
added as the second component.
3. The process has very good atom economy, because that the carbon,
hydrogen and oxygen atoms of the cellulose molecules are very
highly reserved after the catalytic degradation.
4. The hydrogenating degradation of cellulose is preformed under
hydrothermal conditions, so that the reaction system is environment
friendly, and pollution free. Because water is used as reaction
medium, meanwhile no any inorganic acids or bases is involved, the
usual environmental pollution problems is avoided in the cellulose
degradation process.
5. The catalytic process has high yield and selectivity for
ethylene glycol. At optimal reaction conditions, the yield of
ethylene glycol can be over 60%, which promises good application
prospects.
These and other objectives, features, and advantages of the present
invention will become apparent from the following detailed
description, the accompanying drawings, and the appended
claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Example 1
Preparation of Ni--W.sub.2C/AC catalyst: the ammonium metatungstate
and nickel nitrate are mixed at tungsten/nickel weight ratio of
15:1 to obtain a mixed solution, wherein the mass concentration of
ammonium metatungstate is 0.4 g/ml. Then, active carbon (AC) is
impregnated with the mixed solution. After drying at 120.degree. C.
for 12 hours, the catalyst precursor is heated in H.sub.2
atmosphere for temperature-programmed carburization. The detailed
reaction process is as follows: 1.0 g of the catalyst precursor is
loaded in quartz reactor and heated from room temperature to
400.degree. C. in 1 hour, and then to 700.degree. C. at the rate of
1.degree. C./min and maintained for 1 hour for carburization. The
hydrogen flow rate is 60 ml/min. The obtained Ni--W.sub.2C/AC
catalyst with the tungsten loading of 30 wt % and nickel loading of
2 wt % is expressed as Ni--W.sub.2C/AC (2 wt % Ni-30 wt %
W.sub.2C).
With the same condition except changing the concentration of the
ammonium metatungstate and nickel nitrate in the impregnating
solution, or by multiple impregnation, catalysts with different
loadings of catalytic active component can be obtained, wherein the
composition is as follow: a Ni--W.sub.2C/AC catalyst with nickel
loading of 2 wt %, tungsten loading of 5 wt %, 10 wt %, 15 wt %, 60
wt %, or 80 wt %, respectively, as well as a Ni--W.sub.2C/AC
catalyst with tungsten loading of 30 wt %, nickel loading of 0.05
wt %, 0.2 wt %, 5 wt %, 10 wt %, or 30 wt %, respectively.
Example 2
Preparation of Ni--W.sub.xC/AC catalyst: the process is similar to
the example 1. The difference is that the temperature is
850.degree. C. to obtain a Ni--W.sub.xC/AC catalyst with tungsten
loading of 30 wt % and nickel loading of 2 wt %, wherein W.sub.xC
is a mixed crystalline phases of W.sub.2C and WC, 1<x<2,
expressed as Ni--W.sub.xC/AC (2 wt % Ni-30 wt % W.sub.xC).
Example 3
Preparation of W.sub.xC/AC catalyst: the process is similar to the
example 1. The difference is only ammonium metatengstate is used to
obtain the catalyst precursor without adding nickel nitrate, and
the carburization temperature is 800.degree. C. in order to obtain
W.sub.2C/AC catalyst. Otherwise, a higher carburization temperature
of 850.degree. C. is set to obtain W.sub.xC/AC catalyst, which is a
mixed crystalline phases of W.sub.2C and WC, 1<x<2.
Example 4
Preparation of Ru--W.sub.2C/AC catalyst: impregnate the sample of
W.sub.2C/AC as prepared in embodiment 3 with RuCl.sub.3 solution,
then dry it at 120.degree. C. and reduce it at 350.degree. C. for 2
h in hydrogen. The Ru--W.sub.2C/AC (1 wt % Ru-30 wt % W.sub.2C) is
obtained with 1% loading of Ru and 30 wt % loading of W.sub.2C.
Example 5
Preparation of Co--W.sub.2C/AC catalyst: the process is similar to
the example 1, the difference is using cobalt nitrate instead of
nickel nitrate to obtain the catalyst precursor. In the catalyst,
the W loading is 30 wt % and the Co loading is 2 wt %, the catalyst
of Co--W.sub.2C/AC is obtained.
Example 6
Preparation of Fe--W.sub.2C/AC catalyst: the process is similar to
the example 1. The difference is using iron nitrate instead of
nickel nitrate to obtain the catalyst precursor. In the catalyst,
the W loading is 30 wt % and the Fe loading is 2 wt %, the catalyst
of Fe--W.sub.2C/AC is obtained.
Example 7
Preparation of Pt--W.sub.2C/AC catalyst: the process is similar to
the example 1. The difference is using chloroplatinic acid instead
of nickel nitrate to obtain the precursor. In the catalyst, the W
loading is 30 wt % and the Pt loading is 2 wt %, the catalyst of
Fe--W.sub.2C/AC is obtained.
Example 8
Preparation of Ni--WC/Al.sub.2O.sub.3 catalyst: the process is
similar to the example 1. The difference is the support is alumina
instead of active carbon. Meanwhile, the carburization atmosphere
is CH.sub.4/H.sub.2 (volume ratio 1:4) instead of hydrogen. In the
catalyst, the W loading is 30 wt % and the Ni loading is 2 wt %.
The catalyst of Ni--WC/Al.sub.2O.sub.3 is obtained with the WC
phase formation.
Example 9
Preparation of Ni--WC/SiO.sub.2 catalyst: the process is similar to
the example 1, the difference is the support is silica instead of
active carbon. At the same time, the carburization atmosphere is
CH.sub.4/H.sub.2 (methane concentration of 20% v/v), instead of
hydrogen. In the catalyst, the W loading is 30 wt % and the Ni
loading is 2 wt %. The catalyst Ni--WC/SiO.sub.2 is obtained with
the WC phase formation.
Example 10
Cellulose conversion experiment: 1.0 g of cellulose, 0.3 g of
Ni--W.sub.2C/AC catalyst, and 100 ml of water are charged into 200
ml reactor. Then, hydrogen is filled in the reactor to 5 MPa after
three times replacement of the gas therein. The reaction is
performed at 240.degree. C. for 30 min under stirring at 500 rpm.
After the reaction, the liquid products are analyzed with a
high-performance liquid chromatography (HPLC) equipped with a
calcium ion-exchange column to determine the ethylene glycol
concentration. The cellulose conversion is calculated based on the
dried weight of the remaining solid. The liquid production yield is
calculated by the equation: yield (%)=(the products
weight)/(cellulose weight).times.100%. The production yields only
include the target products, which are ethylene glycol and
hexahydric alcohol (including sorbitol and mannitol). The yields of
other liquid products, including propylene glycol, erythritol,
unknown components, and gas products (CO.sub.2, CH.sub.4,
C.sub.2H.sub.6, etc.) are not calculated.
Example 11
The comparison of catalytic performance of Ni--W.sub.2C/AC (2 wt %
Ni-30 wt % W.sub.2C), Ni--W.sub.xC/AC (2 wt % Ni-30 wt % W.sub.xC,
1<x<2) with W.sub.2C/AC (30 wt %), W.sub.xC/AC (30 wt %,
1<x<2), and Ni/AC (2 wt %), see Table 1. The reaction
condition is the same as example 10.
TABLE-US-00001 TABLE 1 The comparison of catalytic performance of
Ni--W.sub.2C/AC, Ni--W.sub.xC/AC W.sub.2C/AC, and W.sub.xC/AC,
Ni/AC Ethylene Cellulose glycol hexahydric Catalyst conversion %
yield % alcohol yield % Others % Ni--W.sub.2C/AC 100 62 6 32
Ni--WxC/AC 100 59 7 34 W.sub.2C/AC 98 27 2 69 WxC/AC 96 24 3 69
Ni/AC 68 5 5 58
As illustrated in the table 1, nickel promoted tungsten carbide
catalyst has a very excellent yield of ethylene glycol.
Example 12
The comparison of the performance of catalysts with different
second metals: Ni--W.sub.2C/AC (2 wt % Ni-30 wt % W.sub.2C),
Ru--W.sub.2C/AC (1 wt % Ru-30 wt % W.sub.2C), Co--W.sub.2C/AC (2 wt
% Co-30 wt % W.sub.2C), Fe--W.sub.2C/AC (2 wt % Fe-30 wt %
W.sub.2C), and Pt--W.sub.2C/AC (1 wt % Pt-30 wt % W.sub.2C), see
Table 2. The reaction condition is the same as example 10.
TABLE-US-00002 TABLE 2 The comparison of the performance of
catalysts with different second metals: Ni--W.sub.2C/AC,
Co--W.sub.2C/AC, Fe--W.sub.2C/AC, and Pt--W.sub.2C/AC Ethylene
Cellulose glycol hexahydric Catalyst conversion % yield % alcohol
yield % Others % Ni--W.sub.2C/AC 100 62 6 32 Ru--W.sub.2C/AC 100 60
7 33 Co--W.sub.2C/AC 82 41 13 31 Fe--W.sub.2C/AC 73 29 6 38
Pt--W.sub.2C/AC 100 48 8 44
As illustrated in the Table 2, all transition metal promoted
tungsten carbide catalysts have very excellent yield of ethylene
glycol, wherein Ni--W.sub.2C/AC catalyst has a yield of ethylene
glycol up to 62%.
Example 13
The comparison of the performance of catalysts with different
supports: Ni--W.sub.2C/AC (2 wt % Ni-30 wt % W.sub.2C),
Ni--WC/Al.sub.2O.sub.3 (2 wt % Ni-30 wt % W.sub.2C), and
Ni--W.sub.2C/SiO.sub.2 (2 wt % Ni-30 wt % W.sub.2C), see Table 3.
The reaction condition is the same as example 10.
TABLE-US-00003 TABLE 3 The comparison of the performance of
catalysts with different supports: Ni--W.sub.2C/AC,
Ni--WC/Al.sub.2O.sub.3, and Ni--W.sub.2C/SiO.sub.2 Ethylene
Cellulose glycol hexahydric Catalyst conversion % yield % alcohol
yield % Others % Ni--W.sub.2C/AC 100 62 6 32 Ni--WC/Al.sub.2O.sub.3
95 35 8 52 Ni--WC/SiO.sub.2 85 38 14 33
As illustrated in the Table 3, all nickel tungsten carbide
catalysts with different supports have good yield of ethylene
glycol.
Example 14
The comparison of the cellulose catalytic conversion over catalyst
Ni--W.sub.2C/AC (2 wt % Ni-30 wt % W.sub.2C) at different
temperatures, see Table 4. The reaction condition is the same as
example 10 except the temperature.
TABLE-US-00004 TABLE 4 The comparison of the cellulose catalytic
conversion over catalyst Ni--W.sub.2C/AC at different temperatures.
Reaction Ethylene hexahydric temperature Cellulose glycol alcohol
.degree. C. conversion % yield % yield % Others % 130 25 8 6 11 190
54 26 8 20 220 100 58 5 37 240 100 62 6 32 250 100 48 9 43 270 100
15 6 79
As illustrated in the Table 4, nickel tungsten carbide catalyst has
a very excellent yield of ethylene glycol within a range of
temperatures. The preferred temperature is about 220-250.degree.
C.
Example 15
The comparison of the cellulose catalytic conversion over catalyst
Ni--W.sub.2C/AC (2 wt % Ni-30 wt % W.sub.2C) with different
reaction time, see Table 5. The reaction condition is the same as
example 10 except the reaction time.
TABLE-US-00005 TABLE 5 The comparison of the cellulose catalytic
conversion over catalyst Ni--W.sub.2C/AC with different reaction
time. Reaction Cellulose Ethylene glycol hexahydric time conversion
% yield % alcohol yield % Others % 10 min 54 24 2 28 30 min 100 62
6 32 3 h 100 51 13 36 5 h 100 24 6 70 24 h 100 16 4 80
As illustrated in the Table 5, nickel tungsten carbide catalyst has
a very excellent yield of ethylene glycol within a range of
reaction time. The preferred reaction time is 30 min-3 h.
Example 16
The comparison of the cellulose catalytic conversion over catalyst
Ni--W.sub.2C/AC (2 wt % Ni-30 wt % W.sub.2C) at different hydrogen
pressures, see Table 6. The reaction condition is the same as
example 10 except the hydrogen pressure.
TABLE-US-00006 TABLE 6 The comparison of the cellulose catalytic
conversion over catalyst Ni--W.sub.2C/AC at different hydrogen
pressures. Ethylene Hydrogen Cellulose glycol hexahydric pressure
Mpa conversion % yield % alcoholyield % Others % 2 31 6 17 8 3 82
32 26 24 5 100 62 6 32 6 100 54 14 32 9 100 28 18 54
As illustrated in the Table 6, nickel tungsten carbide catalyst has
a very excellent yield of ethylene glycol within a range of
hydrogen pressure. The preferred hydrogen pressure is 3-6 MPa.
Example 17
The comparison of the cellulose catalytic conversion over catalyst
Ni--W.sub.2C/AC (30 wt % W.sub.2C) with different nickel loadings,
see Table 7. The reaction condition is the same as example 10.
TABLE-US-00007 TABLE 7 The comparison of the cellulose catalytic
conversion over catalyst Ni--W.sub.2C/AC with different nickel
loadings. Ni Cellulose Ethylene glycol hexahydric content %
conversion % yield % alcoholyield % Others % 0.05 95 6 3 86 0.1 98
55 5 38 2 100 62 6 32 5 85 42 8 35 10 40 18 13 9 30 38 14 14 6
As illustrated in the Table 7, the nickel loading has a certain
effect on the yield of ethylene glycol by using nickel tungsten
carbide catalyst. The preferred nickel loading is 0.1-5 wt %.
Example 18
The comparison of the cellulose catalytic conversion over catalyst
Ni--W.sub.2C/AC (2 wt % Ni) with different tungsten carbide
loadings, see Table 8. The reaction condition is the same as
example 10.
TABLE-US-00008 TABLE 8 The comparison of the cellulose catalytic
conversion over catalyst Ni--W.sub.2C/AC with different tungsten
carbide loadings. Tungsten Cellulose Ethylene glycol hexahydric
Others loading wt % conversion % yield % alcohol yield % % 5 54 22
4 28 10 76 43 6 27 15 83 58 7 18 30 100 62 6 32 60 100 63 12 25 80
85 35 13 37
As illustrated in the Table 8, nickel tungsten carbide catalyst can
realize a very excellent yield of ethylene glycol within a certain
range of tungsten loadings. The preferred loading is 10-60 wt
%.
One skilled in the art will understand that the embodiment of the
present invention as shown in the drawings and described above is
exemplary only and not intended to be limiting.
It will thus be seen that the objects of the present invention have
been fully and effectively accomplished. It embodiments have been
shown and described for the purposes of illustrating the functional
and structural principles of the present invention and is subject
to change without departure from such principles. Therefore, this
invention includes all modifications encompassed within the spirit
and scope of the following claims.
* * * * *